Method of making flexible waste receptacle for marine toilets

ABSTRACT

The invention is a flexible waste receptacle for marine toilets including the process of making such a receptacle. The flexible waste receptacle includes a flexible bag having a filter screen molded in place within the bag to form a first compartment for waste fluid and a second compartment for filtered flush fluid. The flexible bag is formed by a rotational molding process. The appropriate fittings and straps may be heat sealed to the bag to complete the assembly of the flexible waste receptacle.

United States Patent 1 Eichner 1 Jan. 30, 1973 'Assignee:

METHOD OF MAKING FLEXIBLE WASTE RECEPTACLE FOR MARINE TOILETS Inventor: Don W. Eichner, Galesburg, Ill.

Outboard Marine Waukegan, 111.

Filed: May 18, 1970 Appl. No.: 38,429

Corporation,

US. Cl. ..156/245, 156/247, 156/250, 156/253, 156/306 Int. Cl ..B29c 19/00 Field of Search ..156/247, 245, 306, 309, 250, 156/292, 253

References Cited UNITEDSTATES PATENTS 5/1964 Millington ..156/292 X 3,334,008 8/1967 Park et al. ..l56/292 X Primary Examiner-Carl D. Quarforth Assistant ExaminerStephen J. Lechert, Jr. Attorney-Robert K. Gerlin, Robert E. Clemency, Joseph H. Gemignani, Andrew 0. Riteris, Spencer B. Michael, John W. Michael, Gerrit H. Foster, Bayard H. Michael and Paul R. Puerner [57] ABSTRACT The invention is a flexible waste receptacle for marine toilets including the process of making such a receptacle. The flexible waste receptacle includes a flexible bag having a filter screen molded in place within the bag to form a first compartment for waste fluid and a second compartment for filtered flush fluid. The flexible bag is formed by a rotational molding process. The appropriate fittings and straps may be heat sealed to the bag to complete the assembly of the flexible waste receptacle.

5 Claims, 5 Drawing Figures PAIENTEUJAH 30 I975 3.713.937

INVENTO R DON W. EICHNER M FIG. 3

- ATTORN METHOD OF MAKING FLEXIBLE WASTE RECEPTACLE FOR MARINE TOILETS BACKGROUND OF THE INVENTION In many states new legislation regarding water pollution now requires marine toilets in all boats. Although most marine toilets have rigid waste receptacles, a flexible waste receptacle has many advantages. The most important advantage of a flexible waste receptacle is that it is readily adaptable to the contour of the limited space available in many boats. The invention described herein relates specifically to an improved method of making a flexible waste receptacle for marine toilets.

SUMMARY OF INVENTION The invention relates to an improvement in marine toilets, and more particularly to an improved method of making a flexible waste receptacle for marine toilets.

A primary object of this invention is an improved method for making a flexible waste receptacle which can be readily adapted to the limited space available in the bottom of a boat.

A further object is a method of making a flexible waste receptacle which is capable of responding to surging of fluids and gas expansion within the receptacle without any adverse effects.

Anotherobject is an improved process for constructing a flexible waste receptacle including a flexible screen therein for separating the receptacle into a waste fluid compartment and and a filtered fluid compartment.

' Anotherobject is a fast and economical method of making a flexible waste receptacle for receiving the waste fluids from the bowl of a marine toilet.

Other objects and advantages will be apparent from the following description and accompanying drawings for this invention.

THE DRAWINGS FIG. 1 is a prospective view showing two half sections of a mold for the flexible bag and including a filter screen with a protective mask on each side surface.

FIG. 2 is a prospective view showing the adding of a measured amount of liquid plastic to the mold.

FIG. 3is a side view partially in section showing the mold as it appears during the rotational molding process.

FIG. 4 is a prospective view of the invention just after the trimming process and just prior to heat sealing the fittings and straps to the flexible bag.

FIG. 5 is a prospective view of the completed flexible waste receptacle showing the fittings and straps in place.

DETAILED DESCRIPTION culation by a filter screen 14 provided in the bag. The filter screen 14 separates the receptacle into a first compartment 16 for waste fluid and a second compartment 18 for filtered flush fluid. The filter screen 14 is preferably flexible and may be made from a fine mesh material such as vinyl plastic.

The bowl of the toilet is flushed by pumping filtered fluid from the filtered fluid compartment 18 into the bowl. The waste fluid from the bowl is discharged through the bowl outlet and into the waste fluid compartment 16 in the receptacle. Fluid to be recirculated passes through the filter screen 14 into the filtered fluid compartment 18 for recirculation. This movement of fluid is provided by a bilgepump, not shown, emersed within the receptacle. The flexible waste receptacle 10 may be emptied of waste through an outlet opening 20 provided at the bottom of the receptacle.

The flexible bag 12 may be made from a plastic material such as polyvinyl chloride. The plastic used for the bag preferably has a hardness durometer reading between 55 and 65 which provides the desired flexibility. The bag 12 is rotationally molded with the filter screen 14 held in place by a flange 22 at the parting surface 24 of the two half sections of a mold 26.

The waste receptacle 10 may be provided with two fittings consisting of a strain relief bushing 28 and a bag vent fitting 30. The strain relief bushing 28 contains two apertures each adapted to carry an electrical wire leading from the bilge pump. This bushing provides a seal for the wires along with pressure release. The bag vent fitting 30 is adapted to receive a vent hose, not shown.

A bilge pump strap 32 and a hose strap 34 may be provided on the bottom inside surface of the receptacle 10 as shown in FIG. 5. The bilge pump strap 32 is adapted to go around the bilge pump while the hose strap 34 goes over a hose that is attached to the pump.

The initial step in making a flexible waste receptacle 10 is to heat seal a protective mask 36 on each side surface of the filter screen 14. The protective masks 36 may be somewhat smaller in surface area than the filter screen 14 and are placed on the screen such that the screen has an overlap of approximately l/4 inch on the two sides and the bottom. This allows for easy removal of the protective masks 36 and permits the two half sections of the mold 26 to clamp around the screen 14 without interference from the protective masks. The protective masks 36 may be thin vinyl sheets and are preferably heat sealed by use of high frequency radio waves at a temperature of approximately 400 Fahrenheit. The heat sealing process prevents the filter screen 14 from plugging with liquid plastic during the rotational molding process for the flexible bag 12. As soon as the protective masks 36 are in place, the filter screen 14 is placed at the parting surface 24 of the mold as shown in FIG. 1.

FIG. 2 shows the adding of a measured amount of liquid plastic to the mold 26 after each half section has been closed around the filter screen 14. The flexible bag 12 may be 15.25 inches high with a top outside diameter of 13.75 inches and a bottom outside diameter of 20.25 inches. In other words, the flexible bag 12 preferably tapers out from the top of the bag to the bottom of the bag. It has been found that a bag thickness of approximately 0.080 inches works well for the intended use of the bag. For the dimensions given it has been found that approximately seven pounds of polyvinyl chloride is a sufficient quantity of liquid plastic to add to the mold 26.

it should be pointed out that the mold 26 may include a top, not shown, which may be integral with the mold, or a separate part clamped over the top surface of the mold. A top for the mold 26 would completely enclose the liquid plastic within the mold. In this situation one half section of the mold would normally be laid on its side, the liquid plastic poured in, and the other half section of the mold attached to the half section containing the liquid plastic.

After the measured amount of liquid plastic has been added to the mold, it is placed in an oven to be rotated biaxially. This operation is shown in FIG. 3. The biaxial rotation of the mold 26 causes the liquid plastic to cover the interior surfaces of the mold. A mold such as a cast aluminum mold, electro formed mold, or sheet metal mold works well with the invention; It has been found that rotating a cast aluminum mold for a cycle time ranging from four to eight minutes in dry heat reaching approximately 450 Fahrenheit causes the liquid plastic to solidify with the desirable strength and flexibility characteristics. During the rotational molding operation, the filter screen 14 is bonded to the flexible bag 12 in its proper location and position.

When the rotational molding process is completed, the mold 26 is cooled to a temperature of about 125 Fahrenheit. The cooling process may be accomplished quickly by spraying the mold 26 with water at a temperature lower than the mold. At a temperature of 125 Fahrenheit the cured flexible bag 12 may be removed from the mold for trimming the desirable openings.

A top opening 38 of the bag is first trimmed to its proper size and shape. The outlet opening 20 at the bottom of the bag may be trimmed to its desirable dimensions. In addition, openings 40 and 42 for the bag vent fitting 30 and the strain relief bushing 28 may be formed by trimming or punching them in the side of the flexible bag. At this time, the protective masks 36 on each side of the filter screen 14 are also removed and any overlapping of the screen beyond the sides or bottom of the flexible bag may be trimmed away. FIG. 4 shows the flexible waste receptacle after these various steps have been completed.

To complete the construction of the flexible waste receptacle 10, the bilge pump strap 32 and the hose strap 34 are heat sealed to the bottom inside surface of the flexible bag 12. These straps firmly secure the bag 12 to the bilge pump, which is mounted on the inside bottom surface of the bag. In addition, the bag vent fitting 30 and the strain relief bushing 28 are heat sealed to the flexible bag at their respective openings 40 and 42 on the side of the bag. it should be pointed out that the heat sealing process for the straps 32 and 34 and the fittings 28 and 30 may be performed under the same conditions and in the same manner as heat sealing the protective masks 36 to the filter screen.

Last, a nipple 44 may be mechanically attached to the outlet opening 20. This nipple is adapted for attachment to a discharge conduit, not shown, to remove waste fluid from the flexible bag 12. The completed fl ble w t e tacle 10 is hown in 16.5.

'i e fleiiib e sv as e receptacl e 10 con orms readily to various shapes such as the sloping contour of the bottom of a boat. The flexible waste receptacle is also capable of responding to surging of fluids and gas expansion without any adverse effects on the receptacle. In addition, the method of making the receptacle 10 provides a receptacle that reduces the stresses normally produced by the forces of surging of fluids and gas expansion on the seals for the fittings 28 and 30 and the straps 32 and 34.

Various features of the invention are set forth in the following claims:

What is claimed is:

1. A process of making a flexible waste receptacle for marine toilets, said waste receptacle including a flexible bag with a filter screen mounted therein, the process including the steps of: heat sealing a protective mask on each side surface of the filter screen, placing the filter screen at the parting surface of a mold; adding a measured amount of liquid plastic to the mold, and

biaxially rotating the mold to form and cure a flexible bag with the screen mounted therein so as to divide the bag into two compartments.

2. The process of making a flexible waste receptacle as set forth in claim 1 wherein approximately seven pounds of liquid polyvinyl chloride are added to a cast aluminum mold and the mold is biaxially rotated from four to eight minutes in a dry heat of around 450 Fahrenheit.

3. The process of making a flexible waste receptacle as set forth in claim 1 further including the steps of spraying the mold with water to cool it to a temperature of approximately 125 Fahrenheit, trimming an opening at the top of the flexible bag, and removing the protective masks from each side surface of the filter screen.

4. The process of making a flexible waste receptacle as set forth in claim 3 further including the steps of trimming an outlet opening in the bottom of the flexible bag and attaching a nipple to the outlet opening.

5. A process of making a flexible waste receptacle for marine toilets, said waste receptacle including a flexible bag, a filter screen mounted within the flexible bag, a bag vent fitting and a strain relief bushing attached to the flexible bag, and a bilge pump strap and a hose strap including the steps of: heat sealing a protective mask on each side surface of the filter screen; placing the filter :sLcreen at the partingsiirface of a mold, adding 'a meas ured amount of liquid plastic to the mold; biaxially rotating the mold in the presence of dry heat to form and cure the liquid plastic into a flexible bag with the screen mounted therein so as to divide the bag into two compartments; trimming openings for the top of the flexible bag, for a bag vent fitting, for a strain relief bushing, and for an outlet at the bottom of the bag; heat sealing the bilge pump strap and the hose strap to the bottom inside surface of the flexible bag; and heat sealing the bag vent fitting and the strain relief bushing to the flexible bag. 

1. A process of making a flexible waste receptacle for marine toilets, said waste receptacle including a flexible bag with a filter screen mounted therein, the process including the steps of: heat sealing a protective mask on each side surface of the filter screen, placing the filter screen at the parting surface of a mold; adding a measured amount of liquid plastic to the mold, and biaxially rotating the mold to form and Cure a flexible bag with the screen mounted therein so as to divide the bag into two compartments.
 2. The process of making a flexible waste receptacle as set forth in claim 1 wherein approximately seven pounds of liquid polyvinyl chloride are added to a cast aluminum mold and the mold is biaxially rotated from four to eight minutes in a dry heat of around 450* Fahrenheit.
 3. The process of making a flexible waste receptacle as set forth in claim 1 further including the steps of spraying the mold with water to cool it to a temperature of approximately 125* Fahrenheit, trimming an opening at the top of the flexible bag, and removing the protective masks from each side surface of the filter screen.
 4. The process of making a flexible waste receptacle as set forth in claim 3 further including the steps of trimming an outlet opening in the bottom of the flexible bag and attaching a nipple to the outlet opening. 